This invention relates to test instruments for testing of networks, such as LANs (local area networks).
In testing networks, such as LANs, for example, cable faults and the like are desirably detected, since the chance for cable mis-configuration or damage (opens, shorts, split pairs, etc) is always present, and can undesirably impact network performance. In order to test for various conditions, it is necessary to provide some stimulus onto the network or cable, in order to measure the response of the cable or the network. However, the stimulus can often negatively affect network performance, causing data errors or other problems to users of the network.
In network operations, often a question arises regarding the configuration or reliability of a network patch cable. However, existing network test instruments are not adapted to test patch cables of less than 20 feet length. Therefore, the user is left to wonder whether it is a patch cable causing problems. Or, the cable is replaced with an assumed good cable, which can result in waste from throwing away suspected cables when the cable is not the cause of a particular problem. The office environment can be very difficult for cables, as they are often mashed or otherwise abused, which can cause network performance loss. However, the cable may appear otherwise normal to visual inspection.
Finding a particular network cable of interest for testing or inspection can be difficult, especially when a network wiring closet has many cables therein, each having substantially the same size and jacket color.
In accordance with the invention, pseudo-random-number sequences are applied to the network, and the network response is characterized, to determine length, faults, impedance and the like.
Accordingly, it is an object of the present invention to provide an improved apparatus and method for testing networks.
It is a further object of the present invention to provide an improved apparatus and method for determining characteristic impedance of network cables.
It is yet another object of the present invention to provide an improved network test instrument adapted to test short cables.
Another object of the invention is to provide an improved method and apparatus for testing active networks without disturbing network traffic.
A further object of the invention is to provide an improved test instrument that can automatically detect the presence of a cable connection thereto, and begin measurements automatically.
Another object of the invention is to provide an improved network test instrument adapted to drive audio signals over a network.
A further object of the invention is to provide an improved network test apparatus for detecting and classifying Ethernet link pulses.
The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements.